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being analyzed. The detailed responses were also submitted to interested parties and a copy of one <br />of the transmittal letters is enclosed as Attachment A. Again, BMRl believes that the additional <br />data only supplements and contlrms the original study. The additional data being submitted in this <br />document is discussed below. <br />II. Original Geochemical Test Program -Final Results <br />The original geochemical test program included testing of twelve samples from five of the six drill <br />holes in the upper impoundment and seven samples from five of the seven holes it the lower <br />impoundment. The samples were from varying depths in the tailings area so that the potential <br />geochemical changes as a result of the various detoxification methods could be evatluared. The <br />samples were testing in both an unrinsed or deposition state and a rinsed state. Thee rinsing was <br />designed to eliminate any potential buffering material added during ore processing so that long- <br />term acid generation could be evaluated. The testing included acid generating potecntial/acid <br />neutralizing potentials (AGP/ANP), leachability, pore water quality, and humidity cell testing. <br />Results of the AGP/ANP, 1312 leachability and pore water quality were presented and evaluated in <br />the May 1993 Reclamation Evaluation Report. Results of humidity cell testing avatilable to date <br />were also presented and evaluated in the 1993 Report. <br />BMRI indicated in the 1993 Report that humidit}~ cell testing would continue until sulfate values <br />dropped below 10 milligrams/liter (mg/l). Attachment B to this document includes all available <br />humidity cell testing for the original geochemical test program. Note that for ease of review, we <br />have included all test results, including those results in the Reclamation Evaluation. Humidity cell <br />testing ran as long as 75 weeks for one sample, but generally ranged between 20 artd 30 weeks. <br />A review of this information demonstrates quite clearly that the San Luis tailings acre not acid <br />generating even when rinsed to strip away any added buffering capabilities as part of the ore <br />processing. Note that the San Luis Mine geochemical test program contained in the permit <br />application and the quarterly tailings humidity cell testing ongoing since the start c f operations <br />have shown the same results. Thus, there is an extensive geochemical database available to <br />demonstrate that the San Luis tailings are not acid generating. <br />III. Second Sampling Program <br />In September of 1993 BMRI completed the additional drilling program. The program consisted of <br />three holes in the lower impoundment. Two holes (designated Hole # 15 and Hole # 16) were <br />drilled [o a depth of ~5 feet or approximately 38 feet into the tailings disposed when the AVR <br />system was in use. The final hole (designated as Hole #14) met with refusal at approximately 26 <br />feet or 7 feet into the AVR tailings. The holes are located as shown on the enclosed figure. <br />The holes were drilled using vibra core sampling techniques as described in Attaclunent 1 of the <br />October 1, 1993 submittal. Tailings samples were carefully pulled and sealed to puevent any <br />cyanide degradation. Five samples were selected for further testing. These samples included one <br />from Hole #14 at its deepest point (15-26.~ feet), two from Hole #IS and tw'o from Hole #16. All <br />samples were taken from the AVR deposited tailings. <br />2 <br />_/ <br />